Abstract: A cutting guide for precisely setting radial arm and table saw blades in the fabrication of lapped and dado joints comprises a generally wedge shaped body that is formed with a channel at a medial region and a seat at one end. A guide is provided in the channel midway between an inner edge of the seat and the other end of the body. The dimensional relationship among the inner edge of the seat, the other end of the body and the guide is such that when the seat is placed on a piece of lumber with the inner edge of the seat abutting the edge of the lumber and a saw blade is moved to lightly contact the guide, the saw blade is in position to cut halfway into the lumber for making a lap or dado joint.